Many buildings include attic areas which often become quite hot when sunlight is incident on the roof of the building. Such buildings often include insulation to prevent heat transfer between the attic and the rest of the building. The attic thus, at best, becomes simply another room, and, at worse, becomes a heat sink that wastes energy.
The art thus contains several examples of systems intended to take advantage of the heat collection characteristics of a building attic.
While successful in using at least a portion of the heat energy collected in an attic, the presently-available systems are often not fully successful because they do not account for temperature gradients and temperature variations which occur in an attic. For example, one portion of the attic may be hotter than other portions during morning hours, and another portion may be hottest during the afternoon hours. In fact, the exact portion of the attic that is hottest may even vary within the same time period depending on the time of year. Operating a single system at all times, no matter what the precise conditions in the attic are, may be inefficient as well as wasteful of energy.
Therefore, there is a need for a building heating system that uses heat energy located in the attic area of the building in an efficient manner by accounting for temperature variations in the attic and moving only that air having the highest temperature from the attic into the building.